1. Field of the Invention
The present invention relates to a bar code reader and a bar code reading method.
2. Description of the Related Art
In recent years, as represented by POS systems in distributors, the management of goods or the like is generally performed by bar codes. For example, in a POS system of stores and shops, information such as the type and price of an item of goods is coded into the format of a bar code, and the bar code is printed on the goods. Thereafter, checkout is performed by reading the bar code on a cash register, and the number of sold goods are counted on real time. The number of sold goods is totaled, which is useful for stock control and purchase control.
In general, when a bar code is to be read on a cash register, as shown in FIG. 14, a bar code reader 100 is arranged on a counter 102 of a register 101. The reader 100 has an emission window 103 for emitting a laser beam for scanning a bar code. Each emission window 103 is arranged to face an operator S of the reader 100. On the entrance side of the counter 102, i.e., on the right of the emission window 103, a shopping basket X in which a shopper puts the goods is placed. Then, the operator S takes the goods out of the basket X one by one, and passes it in front of the reader 100, and places the goods into a basket Y. At this time, the operator S moves a bar code attached to each item toward the emission window 103. At this time, a laser beam emitted from the emission window 103 scans the bar code, its reflected light is detected by the reader 100, a bar code data based on the reflected light is demodulated, and the demodulation result (e.g., the price of an item) is displayed on a display device 107.
However, the reader 100 described above has the following problems. Namely, when an item of goods taken out of the basket X is a breakable thing, e.g., eggs or tofu, the bar code of the goods is read by the reader 100 once, and, for example, the goods may be temporarily placed between the basket X and the basket Y on the counter 102(called xe2x80x9ctemporary placedxe2x80x9d) (see an item of goods 108 in FIG. 14). Thereafter, as shown in FIG. 15, the temporarily placed goods 108 is stacked on a unbreakable goods contained in the basket Y by the operator S. At this time, the goods 108 is set within the scanning range of the laser beam emitted from each emission window 103, and the bar code of the goods 108 may be read again.
The positions at the baskets X and Y are placed are close to the reader 100, a part of the basket X or the basket Y may be set within the scanning range of the laser beam. In this case, the reader 100 may read the bar code of an item of goods which is contained in the basket X or the basket Y (to be referred to as xe2x80x9cbasket readingxe2x80x9d). In this manner, the same bar code are read twice, the sum total of the prices of the goods may be erroneously calculated.
It is an object of the present invention to provide a bar code reader and a bar code reading method which can prevent the same bar code from being read twice.
The present invention adopts the following configuration to solve the above problems. More specifically, a first aspect of the present invention is a bar code reader. The bar code reader includes: a bar code data detection section for scanning a bar code to detect bar code data; a demodulation data generation section for generating a demodulation bar code data including data of the entire bar code from the bar code data detected by the bar code data detection section; a storage section for storing a plurality of demodulation bar code data generated by the demodulation data generation section; a clocking section for, when the demodulation bar code data is stored in the storage section, every demodulation bar code data, starting clocking of permission time in which the appropriateness of the same demodulation bar code data as the corresponding demodulation bar code data is recognized and of prohibition time in which the appropriateness of the same demodulation bar code data as the corresponding demodulation bar code data is rejected and which is ended after a lapse of the permission time; an area determination section for, when the demodulation bar code data is generated by the demodulation data generation section, specifying the demodulation bar code data as an object to be processed and for determining in which any one of a first area and a second area the demodulation bar code data to be processed is obtained when a scanning range of the bar code is divided by two with respect to a vertical surface; a detection section for, when it is determined by the area determining section that the demodulation bar code data to be processed is obtained in the first area, detecting from the storage section the same demodulation bar code data as the demodulation bar code data to be processed; and a determining section for, when the clocking of the permission time corresponding to the demodulation bar code data detected by the detection section is ended but the clocking of the prohibition time is not ended, determining the demodulation bar code data to be processed as inappropriate demodulation bar code data.
According to the first aspect, when the object to be processed is the same as the demodulation bar code data stored in the storage section, after the permission time of the demodulation bar code data is ended and before the prohibition time is ended, the demodulation bar code data to be processed is regarded as obtained by reading a bar code of temporary placed goods, and the appropriateness of the bar code data is rejected. In this manner, the same bar code can be prevented from being read twice.
A second aspect of the present invention is specified such that the determining section according to the first aspect determines the demodulation bar code data to be processed as appropriate demodulation bar code data when clocking of permission time corresponding to the demodulation bar code data detected by the detection section is not ended.
A third aspect of the present invention is specified such that the determining section according to the first aspect determines the demodulation bar code data to be processed as appropriate demodulation bar code data when it is determined by the area determining section that the demodulation bar code data to be processed is obtained in the second area.
A fourth aspect of the present invention is specified such that the bar code reader according to the first aspect further includes a character length detection section for detecting a character length of the demodulation bar code data to be processed when the demodulation bar code data is constituted by one bar code data obtained by one scanning operation, and an allowable value storage section for storing an allowable value of the character length of the demodulation bar code data, and wherein the determining section determines the demodulation bar code data to be processed as appropriate demodulation bar code data only when the character length detected by the character length detection section is less than the allowable value stored in the allowable value storage section.
A fifth aspect of the present invention is specified such that the bar code reader according to the first aspect further includes a basic character length detection section for, when the demodulation bar code data is constituted by a plurality of bar code data obtained by a plurality of scanning operations, detecting a basic character length which is a bar width per character of each bar code data constituting the demodulated bar code data, and a second determining section for determining the demodulation bar code data as inappropriate demodulation bar code data when the basic character lengths detected by the basic character length detection section do not satisfy a predetermined correlation between the character lengths.
A sixth aspect of the present invention is specified such that the demodulation bar code data according to the fifth aspect is formed by synthesizing a first bar code data and a second bar code data with each other, and the second determining section determines the demodulation bar code data as inappropriate demodulation bar code data when a difference between a basic character length of the first bar code data and a basic character length of the second bar code data is out of a predetermined range.
A seventh aspect of the present invention is specified such that the demodulation bar code data according to the fifth aspect is formed by synthesizing a first bar code data, a second bar code data, and a third bar code data with one another, and the second determining section determines the demodulation bar code data as inappropriate demodulation bar code data when a difference between a basic character length of the first bar code data and a basic character length of the second bar code data is out of a predetermined range or when a difference between a basic character length of the second bar code data and a basic character length of the third bar code data is out of a predetermined range.
An eighth aspect of the present invention is specified such that all the demodulation bar code data stored in the storage section are erased when the clocking section according to the first aspect ends the clocking of the permission time corresponding to the demodulation bar code data which is lastly stored in the storage section.
A ninth aspect of the present invention is specified such that the bar code reader according to the first aspect further includes a first area data storage section for storing the bar code data obtained in the first area of the bar code data detected by the bar code detection section, and a second area data storage section for storing the bar code data obtained in the second area of the bar code data detected by the bar code detection section, and the area determining section determines whether the demodulation bar code data to be processed is generated from the bar code data stored in the first area data storage section or the second area data storage section, thereby to determine whether the demodulation bar code data to be processed is obtained in the first area or the second area.
A tenth aspect of the present invention is specified such that the bar code data detection section according to the first aspect generates a bar code data including a type of data indicating that it is obtained in the first area and the second area, the demodulation data generation section generates a demodulation bar code data including a type of data, and the area determining section determines, based on the type of data included in the demodulation bar code data to be processed, whether the demodulation bar code data to be processed is obtained from the first area or the second area.
An eleventh aspect of the present invention is a bar code reading method including: a bar code data detection step by scanning a bar code to detect bar code data; a demodulation data generation step of generating demodulation bar code data including data of the entire bar code from the bar code data detected in the bar code data detection step; a storage step of storing a plurality of demodulation bar code data generated in the demodulation data generation step; a clocking step of, when the demodulation bar code data is stored in the storage step, every demodulation bar code data, starting clocking of permission time in which the appropriateness of the same demodulation bar code data as the corresponding demodulation bar code data is recognized and of prohibition time in which the appropriateness of the same demodulation bar code data as the corresponding demodulation bar code data is rejected and which is ended after a lapse of the permission time; an area determining step of, when the demodulation bar code data is generated in the demodulation data generation step, specifying the demodulation bar code data as an object to be processed and for determining whether the demodulation bar code data to be processed is obtained in a first area and a second area when a scanning range of the bar code is divided by two with respect to a vertical surface; a detection step of, when it is determined in the area determining step that the demodulation bar code data to be processed is obtained in the first area, for detecting the same demodulation bar code data as the demodulation bar code data to be processed from a plurality of demodulation bar code data stored in the storage step; and a determining step of, when the clocking of the permission time corresponding to the demodulation bar code data detected in the detection step is ended and a clocking of the prohibition time is not ended, determining the demodulation bar code data to be processed as inappropriate demodulation bar code data.
A twelfth aspect of the present invention is specified such that the determining step according to the eleventh aspect determines the demodulation bar code data to be processed as appropriate demodulation bar code data when clocking of permission time corresponding to the demodulation bar code data detected in the detection step is not ended.
A thirteenth aspect of the present invention is specified such that the determining step according to the eleventh aspect determines the demodulation bar code data to be processed as appropriate demodulation bar code data when it is determined in the area determining step that the demodulation bar code data to be processed is obtained in the second area.
A fourteenth aspect of the present invention is specified such that the bar code reading method according to the eleventh aspect further includes a character length detection step of detecting a character length of the demodulation bar code data to be processed when the demodulation bar code data is constituted by one bar code data obtained by one scanning operation, and the determining step determines the demodulation bar code data to be processed as appropriate demodulation bar code data only when the character length detected by the character length detection step is less than a predetermined allowable value.
A fifteenth aspect of the present invention is specified such that the bar code reading method according to the eleventh aspect further includes a basic character length detection step of, when the demodulation bar code data is constituted by a plurality of bar code data obtained by a plurality of scanning operations, detecting a basic character length which is a bar width per character of each bar code data constituting the demodulated bar code data, and a second determining step of determining the demodulation bar code data as inappropriate demodulation bar code data when basic character lengths detected in the basic character length detection step do not satisfy a predetermined correlation between the character lengths.
A sixteenth aspect of the present invention is specified such that the demodulation bar code data according to the fifteenth aspect is formed by synthesizing a first bar code data and a second bar code data with each other, and the second determining step determines the demodulation bar code data as inappropriate demodulation bar code data when a difference between a basic character length of the first bar code data and a basic character length of the second bar code data is out of a predetermined range.
A seventeenth aspect of the present invention is specified such that the demodulation bar code data according to the fifteenth aspect is formed by synthesizing a first bar code data, a second bar code data, and third bar code data with each other, and the second determining step determines the demodulation bar code data as inappropriate demodulation bar code data when a difference between a basic character length of the first bar code data and a basic character length of the second bar code data is out of a predetermined range or when a difference between a basic character length of the second bar code data and a basic character length of the third bar code data is out of a predetermined range.
An eighteenth aspect of the present invention is specified such that all the demodulation bar code data stored in the storage section are erased when the clocking step according to the eleventh aspect ends the clocking of the permission time corresponding to the demodulation bar code data which is lastly stored in the storage step.
A nineteenth aspect of the present invention is a bar code reader. The reader includes: a light receiving section for receiving reflected light from a bar code scanned by a scanning light to output an electric signal corresponding to an amount of received light; a demodulation section for demodulating the electric signal output from the light receiving section to generate a demodulation bar code data; a storage section for storing the demodulation bar code data; a clocking section for starting clocking of first time when the demodulation bar code data is stored in the storage section; an area determining section for determining whether the demodulation bar code data demodulated by the demodulation section is scanned in a first area and a second area which are obtained by dividing a scanning range of the scanning light; a discriminating section for determining whether the demodulated bar code data coincides with the demodulation bar code data which was demodulated prior to the demodulation bar code data and stored in the storage section; and a determining section for determining the demodulation bar code data as inappropriate demodulation bar code data when the bar code data is scanned in the first area, when it is determined by the discriminating section that the demodulated bar code data coincides with already demodulated bar code data, and when the first time has elapsed. In the nineteenth aspect, the number of divided scanning ranges is not limited.
A twentieth aspect of the present invention is a bar code reader. This reader includes: a light receiving section for receiving reflected light from a bar code scanned by a scanning light to output an electric signal corresponding to an amount of received light; a demodulation section for demodulating the electric signal output from the light receiving section to generate a demodulation bar code data; a storage section for storing the demodulation bar code data; an area determining section for determining whether the demodulation bar code data demodulated by the demodulation section is scanned in a first area and a second area which are obtained by dividing a scanning range of the scanning light; a discriminating section for determining whether the demodulated bar code data coincides with the demodulation bar code data which was demodulated prior to the demodulation bar code data and stored in the storage section; and a determining section for determining the demodulation bar code data as inappropriate demodulation bar code data when the bar code data is scanned in the first area and when it is determined by the discriminating section that the demodulated bar code data coincides with already demodulated bar code data.